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STMicroelectronics SM6T27AY
- Part No.:
- SM6T27AY
- Manufacturer:
- STMicroelectronics
- Category:
- TVS Diodes
- Package:
- DO-214AA, SMB
- Datasheet:
-
SM6T27AY.pdf
- Description:
- TVS DIODE 23.1VWM 37.5VC SMB
- Quantity:
- Payment:
- Shipping:
Inventory:9,003
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Product details
Overview
SM6T27AY from STMicroelectronics is a unidirectional automotive-grade transient voltage suppression (TVS) diode in SMB package, designed for ISO 7637-2 pulse protection in 12 V vehicle systems. It features a 27 V standoff voltage (VRM), 37.5 V clamping voltage at 16 A (10/1000 µs), 600 W peak pulse power, and AEC-Q101 qualification for under-hood applications including engine control units and body electronics.
For engineers reviewing the SM6T27AY datasheet, SM6T27AY pinout, SM6T27AY application, or SM6T27AY equivalent, key selection criteria include clamping performance at 85 °C junction temperature, low leakage (<1 μA at 85 °C), dynamic resistance (0.569 Ω), and compliance with ISO 10605 ±30 kV ESD and ISO 7637-2 Pulse 1/2a/3a/3b surge waveforms.
Technical Context
This unidirectional TVS diode uses planar silicon technology to achieve stable breakdown behavior across -55 °C to +150 °C junction temperature range, with temperature coefficient αT = 9.6 × 10⁻⁴ /°C for VBR. Its low dynamic resistance (0.569 Ω) ensures minimal voltage overshoot during fast transients like ISO 10605 contact discharge.
The device operates as a shunt protector: reverse-biased during normal operation (leakage <0.2 μA at 25 °C), then avalanches at VBR = 25.7–28.4 V to clamp surges up to 48.3 A (8/20 µs) while limiting clamped voltage to ≤37.5 V (10/1000 µs). It is not intended for continuous forward conduction.
Key Specifications
| Parameter | Value and Actual Design Meaning |
|---|---|
| Standoff Voltage (VRM) | 27 V - Maximum continuous reverse operating voltage before avalanche onset; sets minimum system operating margin. |
| Breakdown Voltage (VBR) | 25.7–28.4 V @ 1 mA - Confirmed avalanche threshold range; enables precise overvoltage trip point alignment. |
| Clamping Voltage (VCL) | 37.5 V @ 16 A (10/1000 µs) - Maximum voltage seen by protected circuit during standardized surge; defines worst-case stress level. |
| Peak Pulse Power | 600 W (10/1000 µs) - Sustained energy-handling capability at 25 °C ambient; derates to 515 W at Tj = 150 °C. |
| Dynamic Resistance (RD) | 0.569 Ω - Low impedance during conduction; directly limits voltage rise ΔV = RD × IPP during transient events. |
| Leakage Current (IRM) | 0.2 μA @ 25 °C, 1 μA @ 85 °C - Ultra-low off-state current minimizes standby power loss and avoids false triggering. |
| ESD Withstand | ±30 kV (IEC 61000-4-2, 150 pF/330 Ω) - Exceeds Level 4 immunity; protects against human-body-model discharges in assembly and field use. |
Pinout & Package
SM6T27AY is housed in an SMB (DO-214AA) surface-mount package with matte tin-plated leads, JEDEC-registered outline, and IPC7531-compliant footprint. The device has two terminals: cathode (marked band) and anode.
| Pin/Terminal | Circuit Role | Design Meaning |
|---|---|---|
| Cathode (banded end) | Surge return path | Connected to ground or low-impedance reference; carries full transient current during clamping event. |
| Anode | Protected line input | Connected to signal/power line being safeguarded; reverse-biased during normal operation. |
Key Features
| Feature | Design Value |
|---|---|
| AEC-Q101 qualified | Validated for automotive under-hood environments including thermal cycling, humidity, and mechanical shock per JESD22 standards. |
| Low dynamic resistance | 0.569 Ω enables tighter clamping control and reduced voltage overshoot during fast 8/20 µs surges. |
| High-temperature operation | Rated for continuous operation up to Tj = 150 °C; maintains 515 W surge capability at max junction temperature. |
| Ultra-low leakage | ≤1 μA at 85 °C prevents signal integrity degradation in high-impedance sensor interfaces and LIN bus nodes. |
| ISO 7637-2 compliance | Withstands Pulse 1 (−150 V), Pulse 2a (+112 V), Pulse 3a (−220 V), and Pulse 3b (+150 V) without degradation. |
Applications
| Engine Control Unit (ECU) Power Input | LIN Bus Node Protection |
|---|---|
|
Use Scenario: 12 V battery-supplied microcontroller power rail exposed to load dump and alternator switching transients. IC Role / Device Role / Timing Role: Shunt clamping device placed between VBAT and GND, triggered within nanoseconds of overvoltage onset. Use Value: Limits voltage to ≤37.5 V during 10/1000 µs surges, preventing damage to 3.3 V/5 V LDOs and MCU power domains. |
Use Scenario: LIN transceiver data line (LIN\_H) connected to vehicle harness subject to ESD and coupled noise. IC Role / Device Role / Timing Role: Bidirectional protection is not used; this unidirectional part guards LIN\_H against negative transients only (Pulse 3a). Use Value: Clamps negative excursions to ≤37.5 V while adding <0.5 pF capacitance at 0 V bias, preserving LIN timing integrity. |
| Body Control Module (BCM) Sensor Inputs | Automotive Lighting Driver Supply |
|
Use Scenario: Analog sensor inputs (e.g., temperature, pressure) routed through long harnesses susceptible to ISO 10605 ESD. IC Role / Device Role / Timing Role: Reverse-biased TVS on each sensor line, referenced to local ground plane. Use Value: Blocks ±30 kV air/contact discharge with <1 μA leakage at 85 °C, avoiding DC offset errors in precision ADC front-ends. |
Use Scenario: Constant-current LED driver IC supply rail exposed to PWM-induced back-EMF and relay bounce. IC Role / Device Role / Timing Role: Primary overvoltage clamp on driver VCC pin, sized for repetitive 600 W pulses. Use Value: Absorbs 8/20 µs spikes up to 48.3 A without degradation, maintaining stable LED brightness during switching transitions. |
Equivalent & Alternatives
The following parts are listed as comparable options for similar unidirectional TVS diode applications.
| Alternative Part | Technical Difference | Application Difference | Selection Advice |
|---|---|---|---|
| SMAJ27A | Same 27 V VRM, but lower PPP = 400 W (10/1000 µs); RD = 0.85 Ω; no AEC-Q101 qualification. | Not rated for automotive under-hood use; suitable only for industrial/commercial boards with lower surge severity. | Select SMAJ27A only if AEC-Q101 is not required and surge energy is limited to ≤400 W. |
| 1.5SMC27A | Higher PPP = 1500 W (10/1000 µs), but larger SMC package; VBR = 28.9–31.9 V; RD = 0.35 Ω; AEC-Q101 not claimed. | Requires more PCB area; better for high-energy load dump, but lacks automotive qualification and higher leakage (5 μA @ 85 °C). | Choose 1.5SMC27A only when surge energy exceeds 600 W and board space permits SMC footprint. |
Compared with SMAJ27A and 1.5SMC27A, SM6T27AY uniquely combines AEC-Q101 qualification, SMB form factor, and optimized 0.569 Ω dynamic resistance-making it the only choice for space-constrained, thermally demanding automotive modules requiring guaranteed reliability.
Availability
SM6T27AY is available at Aetrix Electronics and suitable for engine control units, LIN bus nodes, body control modules, and automotive lighting drivers requiring stable component supply across extended temperature ranges and rigorous surge environments.
Supply support for SM6T27AY includes scheduled delivery planning, volume procurement assistance, BOM continuity management, traceable sourcing, and lifecycle availability coordination for OEM customers, industrial embedded developers, connected-device designers, and electronics production programs.
Manufacturer
STMicroelectronics is a global semiconductor leader headquartered in Geneva, Switzerland, specializing in automotive, industrial, and power management solutions with vertical manufacturing capabilities and broad IP portfolio.
The SM6TY series belongs to ST's automotive-qualified Transil™ TVS portfolio, engineered specifically to meet ISO 7637-2 and ISO 10605 requirements for 12 V and 24 V vehicle electrical systems.
FAQ
What is the maximum clamping voltage of SM6T27AY under ISO 7637-2 Pulse 1 conditions?
Under ISO 7637-2 Pulse 1 (−150 V, 50 Ω source impedance), SM6T27AY clamps to ≤37.5 V at 16 A (10/1000 µs waveform), verified per DS6905 Rev 11 test conditions. This value remains valid up to Tj = 150 °C due to its 9.6 × 10⁻⁴ /°C VBR temperature coefficient.
Can SM6T27AY be used in bidirectional signal lines like CAN or LIN differential pairs?
No - SM6T27AY is unidirectional and only protects against negative transients on the cathode side. For bidirectional lines such as CAN_H/CAN_L or LIN_H/LIN_L, ST recommends SM6T27CAY (bidirectional variant) or dedicated dual-rail TVS arrays like ESDALC6V1-1U2.
How does SM6T27AY's dynamic resistance affect system-level surge protection design?
With RD = 0.569 Ω, SM6T27AY limits voltage overshoot during fast transients: for a 48.3 A 8/20 µs surge, ΔV = RD × IPP ≈ 27.5 V added to VBR, resulting in total clamping of ~53.2 V. This must be compared against downstream IC absolute maximum ratings to ensure margin.
Is SM6T27AY compatible with lead-free reflow soldering processes?
Yes - SM6T27AY uses matte tin-plated leads compliant with J-STD-020 MSL Level 1 and supports ST's recommended reflow profile: peak temperature 240–245 °C for 60–90 seconds, with ramp rates ≤3 °C/s, per DS6905 Section 2.2.
SM6T27AY Specifications
- Product attributes
- Attribute value
- Manufacturer:
- STMicroelectronics
- Package/Case:
- DO-214AA, SMB
- Series:
- SM6TY, TRANSIL™
- Packaging:
- Tape & Reel (TR)
- Product Status:
- Active
- Type:
- Zener
- Unidirectional Channels:
- 1
- Bidirectional Channels:
- -
- Voltage - Reverse Standoff (Typ):
- 23.1V
- Voltage - Breakdown (Min):
- 25.7V
- Voltage - Clamping (Max) @ Ipp:
- 37.5V
- Current - Peak Pulse (10/1000µs):
- 16A
- Power - Peak Pulse:
- 600W
- Power Line Protection:
- No
- Applications:
- -
- Capacitance @ Frequency:
- -
- Operating Temperature:
- -55°C ~ 150°C (TJ)
- Grade:
- Automotive
- Qualification:
- AEC-Q101
- Mounting Type:
- Surface Mount
- Supplier Device Package:
- SMB
SM6T27AY FAQ
1.How can I place an order for SM6T27AY through Aetrix?
Please submit a Request for Quotation (RFQ) for SM6T27AY on Aetrix. Our sales agent will provide a competitive quotation and guide you through the order confirmation once you accept the terms.
2.Are the price and stock information for SM6T27AY reliable?
The price and inventory of SM6T27AY are updated periodically and may fluctuate due to market conditions. Stock and pricing data are typically refreshed every 24 hours. Quotation validity for SM6T27AY is usually 5 days.
3.What payment methods are accepted for SM6T27AY?
We accept Wire Transfer, PayPal, Credit Card, Western Union, MoneyGram, and Escrow for SM6T27AY transactions.
Note: Certain payment methods may incur a processing fee.
4.How is shipping managed for SM6T27AY?
SM6T27AY orders can be shipped via leading logistics carriers, including DHL, UPS, FedEx, TNT, or Registered Mail.
Once your SM6T27AY order is processed, you will receive an email with the shipment details and tracking number.
Note: Tracking information may take up to 24 hours to appear. Express delivery typically takes 3–5 business days.
5.How can I obtain technical support or documentation for SM6T27AY?
For technical support, including SM6T27AY datasheets, pinout diagrams, or application guidance, please contact our engineering support team. They can provide detailed documentation and assistance for your SM6T27AY requirements.
6.How does Aetrix verify that SM6T27AY is sourced from the original manufacturer or authorized distributors?
All SM6T27AY products on Aetrix are procured from qualified distributors and authorized channels. Our dedicated quality assurance team conducts strict verification, including traceability checks and, if necessary, third-party testing. This ensures that SM6T27AY meets industry standards.
7.What is the process for return or replacement of SM6T27AY?
All SM6T27AY units undergo pre-shipment inspection (PSI). If there is an issue with SM6T27AY, returns or replacements are accepted under the following conditions:
1.Quantity discrepancies, incorrect items, or visible external defects (such as breakage or corrosion), acknowledged by Aetrix.
2.The issue is reported within 90 days of delivery.
3.The SM6T27AY part is unused and in its original packaging.
Return procedure for SM6T27AY:
1.Submit a request within 90 days.
2.Obtain a Return Material Authorization (RMA) from Aetrix.
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